Most passenger vehicles and many other types of motor vehicles have a cigar or cigarette lighter unit installed on the instrument panel or dashboard as standard equipment. Such unit includes a fixedly mounted socket and a lighter member which is removably received in the socket. The size and shape of the socket and lighter member are standarized in vehicles manufactured in the United States.
Tyically, such a lighter unit is not used as a means of supplying electrical power to electrical and electronic accessories on the instrument panel or at other locations in the vehicle itself. This is probably due to the fact that such use prevents ready access to the lighter function in that it would prevent use of the lighter member. Also, the socket of the lighter unit is not used as means for mounting accessory devices or equipment. This latter drawback is probably due to the fact that the size of the accessories which might be mounted prohibits such use. Also, such mounting would prevent the use of the lighter function. Furthermore, accessories, such as lamps or the like, which do use the lighter socket for electrical power do not require continuous power to be effective as do electronic devices having memories, such as calculators, clocks, computers and the like.
Thus, in view of the foregoing, there is a need for a convenient source of electrical power for electronic and electrical accessories in a vehicle, which accessories augment the factory-supplied information and comfort devices on the instrument panel and in the general area of the driver of the vehicle. By a convenient source is meant such a source which requires no special skills or significant effort to use or install in place. To provide such a convenient source of electric power for memory-based devices, such as clocks, calculators, computers and the like, the following criteria should be satisfied to provide acceptance by a wide audience of vehicle drivers:
1. There must be a suitable mounting place for the accessory, one which does not detract from the decor of the instrument panel or the interior of the vehicle and one which does not block the view of other accessories near the driver;
2. The cigarette lighter capability must be retained if possible although the fact that more and more people are non-smokers or are becoming so permits the elimination of the lighter capability in certain cases;
3. The power source must be readily installable in a cigarette lighter socket by persons without special skills or who are not mechanically inclined;
4. The power source should be secured against theft even if it requires extra cost.